JPH04278796A - External environment adaptive volume adjustment method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is an audio device used by individuals (for example, an audio device for listening to sound through earphones or headphones).
The present invention relates to an external environment adaptive sound volume adjustment method for minimizing sound leakage to the outside of an audio device. In recent years, audio devices using earphones and other devices have been used in public places such as trains, but it is necessary to increase the volume especially in places where there is a lot of external noise, so it is necessary to increase the volume to prevent sound leakage to the outside of the audio device. What is desired is a structure in which this can be avoided as much as possible.

0002

[Prior Art] In order to suppress sound leakage to the outside, conventional audio equipment has a method of attenuating sound at frequencies that easily leak to the outside (shaky sound), and an output section that is partially open from the perspective of sound quality. The method used was to make it a closed type.

0003

[Problems to be Solved by the Invention] However, in the method of attenuating a predetermined frequency, a part of the original sound information is lost and the balance of the sound is lost, and the user cannot be fully satisfied. In addition, in the method of making the output part a sealed type,
Due to its size limitations, it was difficult to create a completely sealed structure.

[0004] Incidentally, the volume of sound leaking to the outside that causes discomfort to others has a relative relationship with the level of external noise. Furthermore, the volume requested by the user is also influenced by the level of external noise. That is, when the external noise is small, the volume emitted from the output section (earphones, etc.) of the audio device may be small, and naturally the leakage of sound to the outside is also reduced. Conversely, if the external noise is large, it becomes necessary to increase the volume emitted from the output section of the audio device, which naturally increases the sound leakage to the outside, but some of it is drowned out by the external noise and its influence is reduced. is reduced.

[0005] The problem with the conventional method is that it is troublesome to adjust the volume of the audio device each time even if the external noise becomes temporarily quiet in an environment where the external noise is not constant. The problem is that the volume leaking from the output section to the outside becomes large and becomes a nuisance. SUMMARY OF THE INVENTION An object of the present invention is to provide an external environment adaptive volume adjustment method that can automatically set an optimal volume depending on the external environment.

[0006]

[Means for Solving the Problems] The external environment adaptive sound volume adjustment method according to claim 1 detects a noise level outside an audio device, and adjusts the volume of sound emitted by the audio device according to a tendency of change in the noise level. It is characterized by changing the control of The external environment adaptive sound volume adjustment method according to claim 2 is the external environment adaptive sound volume adjustment method according to claim 1, in which when the amount of change in the external noise level of the audio device is on an upward trend, the method adjusts the sound volume in a short period of time. Further, when the amount of change in the noise level is on a downward trend or is constant, the average value of the noise level is detected over a long period of time, and the control of the volume emitted by the acoustic device is changed.

[0007] In the external environment adaptive volume adjustment method according to claim 3, in the external environment adaptive volume adjustment method according to claim 1, when the external noise level of the audio device is increasing or remains constant, The present invention is characterized in that when the noise level is on a decreasing trend, the average value of the noise level is detected over a short period of time, and the control of the volume emitted by the acoustic device is changed.

[0008]

[Operation] The invention according to claim 1 increases the volume when the external noise level of the audio device becomes higher than the initial volume setting of the audio device, and increases the volume when the external noise level decreases. By reducing the volume, the influence of the volume leaking to the outside on others can be relatively reduced.

[0009] The invention according to claim 2 shortens the predetermined period for calculating the average value of the noise level when the amount of change in the noise level is on an upward trend (particularly in the direction of decreasing noise level). You can adjust the volume to reduce the volume leaking to the outside. According to the third aspect of the invention, by shortening the predetermined period for determining the average value of the noise level when the noise level is decreasing, the volume can be quickly adjusted to reduce the volume leaking to the outside. can.

[0010] In other words, by determining the noise level as an average value over a predetermined period, it is possible to accurately grasp the change trend of the noise level used for volume adjustment, thereby avoiding unnecessary volume adjustment and adjusting the volume to a level that is comfortable for the user. can be enjoyed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the basic configuration of an audio device to which the method of the present invention is applied. In the figure, the audio device includes a sound generation section 11 that generates an electrical signal having acoustic information to be output, and a volume control section 13 that controls the volume by adjusting the level (amplification factor) of the electrical signal according to the volume setting. and a sound output section 15 that inputs a level-adjusted electric signal to vibrate the vibrating section and emit sound.The present invention also has a configuration that monitors the noise level outside the acoustic device and outputs the sound. An external volume monitor unit 17 is provided which sends level information as an electrical signal to the volume control unit 13 for volume control.

The method of the present invention will now be described in detail with reference to FIG. 2, which shows an embodiment of the configuration of the volume control section 13, and FIG. 3, which shows an example of a volume control procedure. The volume level signal input in response to the user's volume operation is input to the volume level setting unit 21 of the volume control unit 13, and is stored as a gain G initially set in the gain calculation unit 22, and is Set the desired volume. In addition, the noise level β outside the audio device detected by the external volume monitor unit 17
The environmental sound level signal representing the above is input to the volume level setting section 21 and the difference detection section 23. Volume level setting section 21
In this case, the environmental sound level signal is captured using the input of the volume level signal as a trigger, the noise level β at the time of setting the volume level is stored, and is output to the difference detection unit 23 as the initial noise level α.

[0013] The difference detection section 23 sequentially detects the noise level β.
The difference amount Δd between the noise level α and the initial noise level α is detected, and it is further detected whether this difference amount Δd is trending upward or downward. The difference amount Δd is sent to the difference amount integration processing section 24, and the change tendency information of the difference amount Δd is sent to the integration time calculation section 25. The integral time calculation unit 25 sets the integral time t to a small value when the difference amount Δd is on an upward trend, and sets the integral time t to a large value when the difference amount Δd is on a downward trend. The difference amount integration processing unit 24 integrates the difference amount Δd according to the integration time t set by the integration time calculation unit 25, calculates the average change amount ΔG in the integration time t, and sends it to the gain calculation unit 22.

The gain calculation unit 22 calculates the gain g to be set in the amplification unit 26, taking into account the initially set gain G and the average variation ΔG. The electrical signal input from the sound generating section 11 is outputted via the amplifying section 26 which performs amplification processing using the obtained gain g. In this way, the gain g set in the amplification section 26 is automatically changed according to changes in the noise level outside the audio device, with the volume level set by the user's volume operation as the initial value. For example, if the sign of the average amount of change ΔG when the noise level changes in the direction of increasing is positive, the gain set in the amplification unit 26 is calculated by calculating the sum with the gain G initially set in the gain calculation unit 22. changes to increase g. In other words, the volume can be increased as the noise level increases. Note that at this time, the volume leaking to the outside becomes relatively large, but since the noise level is also large, the impact on others is small.

On the other hand, when the noise level changes in the direction of decreasing, the sign of the average change amount ΔG becomes negative, and by calculating the sum with the gain G initially set in the gain calculating section 22, the sign of the average change amount ΔG becomes negative. The set gain g can be decreased. That is, as the noise level decreases, the volume can be lowered, the volume leaking to the outside can be relatively reduced, and the influence on others can be similarly reduced.

Incidentally, the increase/decrease in the gain g in the present invention is as follows:
Rather than responding instantly to changes in the noise level outside the audio equipment, the amount of change in the monitored noise level (difference Δd) is
By integrating the value over a predetermined time and calculating the average value to calculate the increase/decrease (average change ΔG) in the gain g, drastic changes in the volume can be suppressed. Also,
When the change in the monitored noise level is on the rise, it is a phenomenon that the external noise is changing rapidly. By shortening the integration time to obtain the average value, the increase or decrease in volume can be quickly followed by the change. can be done. In other words, when external noise suddenly increases or decreases, the volume emitted by the audio device is quickly increased or decreased accordingly, and especially when external noise decreases, the volume leaking to the outside is quickly reduced. By doing so, you can avoid causing trouble to others. On the other hand, when the change in the monitored noise level is on a downward trend (including a constant trend), this is a phenomenon in which the change in external noise is converging or slow, so by increasing the integration time to obtain the average value, This makes it easier to listen to music by avoiding the need to increase or decrease the volume in response to minute changes in external noise.

Furthermore, in the embodiment described above, the integration time t is set in the integration time calculation section 25 depending on whether the difference amount Δd is on an upward trend or a downward trend, but if the noise level β increases If there is a tendency, the integral time t may be lengthened, and if there is a decreasing trend, the integral time t may be shortened. In other words, the volume leaking to the outside of the audio equipment often becomes a problem when the external noise is relatively low.
When the external noise becomes small, by shortening the integration time t and quickly adjusting the volume, the volume leaking to the outside can be effectively reduced.

FIG. 4 is a diagram showing the structure of an example of the sound output section (earphone) used in the audio device of this example. (a) shows its appearance, and (b) shows its cross-sectional structure. In the figure, reference numeral 41 is a speaker (diaphragm) which is a main component of the sound output section 15, and reference numeral 42 is a sound collection microphone as the external volume monitor section 17 provided on the back of the speaker 41. Therefore, when the user is using this audio device, the sound collecting microphone 42 faces outward, and the noise level outside the audio device can be effectively monitored.

Note that even if the sound collection microphone 42 detects the sound of the acoustic device itself output from the speaker 41, the volume control unit 13 can recognize the sound emitted by the device itself.
It is also easy to avoid using that sound component for volume control. Further, it is also easy to perform volume control based on the ratio between the sound emitted by the device itself and external noise, and in this case, even more effective control of leakage volume becomes possible.

Furthermore, although the embodiments described above are applied to, for example, a portable cassette tape playback device and earphones (headphones), they can be similarly applied to, for example, public telephones or mobile telephones.

[0021]

[Effects of the Invention] As explained above, the present invention allows the volume emitted from the audio device to be automatically adjusted according to changes in noise in the external environment. The sound device can be used at a higher volume. In addition, when adjusting the volume of the audio device, the volume leaking to the outside also changes at the same time, but especially when the external noise changes in the direction of decreasing, the volume can be quickly reduced, so the volume leaking becomes relatively small. It is possible to reduce the discomfort caused to others by the leaked sound.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of an audio device to which the method of the present invention is applied.

FIG. 2 is a block diagram showing the configuration of an embodiment of a volume control section according to the present invention.

FIG. 3 is a flowchart illustrating an example of a volume control procedure according to the present invention.

FIG. 4: Sound output section (
FIG. 2 is a diagram showing an example structure of an earphone.

[Explanation of symbols]

11 Sound generator 13 Volume control section 15 Sound output section 17 External volume monitor section 21 Volume level setting section 22 Gain calculation section 23 Difference detection section 24 Difference integral processing section 25 Integral time calculation section 26 Amplification section 41 Speaker (diaphragm) 42 Sound collection microphone

Claims (3)

[Claims] 1. A sound volume adjustment method adapted to an external environment, comprising: detecting a noise level outside an audio device; and changing control of the volume emitted by the audio device in accordance with a tendency of change in the noise level. [Claim 2] When the amount of change in the noise level outside the acoustic device is on an upward trend, the average of the noise level is determined over a short period of time, and when the amount of change in the noise level is on a downward trend or is constant, the average of the noise level is determined over a long period of time. 2. The external environment adaptive sound volume adjustment method according to claim 1, wherein the sound volume is detected based on a value and the control of the sound volume emitted by the audio device is changed. 3. When the noise level outside the acoustic device is increasing or constant, the noise level is detected over a long period of time, and when the noise level is decreasing, the average value of the noise level is detected over a short period of time. 2. The external environment adaptive volume adjustment method according to claim 1, further comprising changing the control of the volume emitted by the audio device.